PUERTO VALLARTA, Mexico — Hurricane John churned parallel to Mexico's resort-studded Pacific Coast, lashing beaches with winds and rain and plotting a course that could take its center close to land before nicking the tip of Baja California.

Authorities in Puerto Vallarta, among Mexico's most-visited resorts, scrambled to prepare emergency shelters while organizing night patrols to hunt for possible storm-related damage late Wednesday. But tourists and residents alike remained calm, even as the Category 3 hurricane rumbled closer.

The hurricane grew into a Category 4 storm on Wednesday but dropped back to a Category 3 after losing some wind speed. Still, it had maximum sustained winds of 125 mph, and stronger gusts capable of ripping roofs off buildings and causing storm surges of up to 18 feet above normal. Most of its fury was felt out to sea, however, with its most damaging winds failing to touch the mainland.

At 2 a.m. local time the hurricane was located 70 miles west southwest of the resort and port city of Manzanillo. It moving west northwest near 14 mph with winds up to 125 mph.

Forecasters at the U.S. national weather center in Miami warned that the storm could drop up to 18 inches of rain in some places and create up to a 5-foot storm surge on the coast. The weather center warned of "life-threatening flash floods and mudslides" in mountain areas.

The storm was expected to strengthen in coming hours, however, and Mexico issued hurricane warnings for about 400 miles of coast from the port of Lazaro Cardenas to the fishing and shipping community of San Blas, an area encompassing the bay that holds the resort of Puerto Vallarta.

Unlikely threat to U.S.Forecasters said John wasn't likely to affect the United States, cooler Pacific waters tend to diminish the storms before they reach California. Instead, it was expected to skirt close to Mexico's Pacific Coast and head for the Baja California Peninsula by Friday.

The Mexican government also issued a hurricane warning for parts of the southern Baja Peninsula, including the resort city of Cabo San Lucas.

William Rousseau, an Oregon tourist vacationing with his family, said Puerto Vallarta hotel officials had warned about the storm, "but we're calm because they say it's not going to hit this city."

"We're continuing to enjoy the city," he said. "They just asked us not to go into the ocean or on any bay tours."

Officials postponed the arrival of a Carnival cruise ship, prohibited customary tours of the bay and announced public schools would be closed Thursday. Puerto Vallarta Mayor Gustavo Gonzales said 50 shelters had been readied, and emergency crews prepared to patrol throughout the night.

Some coastal communities in Jalisco state, where Puerto Vallarta is located, were being evacuated because of their proximity to two dams, state authorities said.

The sense of urgency was higher still in another resort city, Cabo San Lucas, where fishermen and authorities were hurriedly preparing for John's arrival.

"We are preparing shelters for the evacuation of civilians, if that becomes necessary," said Luis Armando Diaz, mayor of Los Cabos, on Baja's southern tip. "According to the information we have, the storm is coming right toward Los Cabos."

Cabo San Lucas Port Captain Everardo Jimenez said he had instructed the operators of a tourist boat to get the craft out of the water.

Forecasters predict 'torrential downpours'Back on the mainland and closer to the storm's current location, tropical storm-force winds and endless if relatively light rain were reported in the resort cities of Ixtapa and Zihuatanejo, as well as Lazaro Cardenas, Mexico's deepest port.

The National Hurricane Center in Miami said while the center of John is forecast to remain just offshore, hurricane-force winds were expected to begin raking beaches near Puerto Vallarta by Thursday. The storm was predicted to arrive in Los Cabos a day later, before heading out to sea.

Forecasters predicted up to 10 inches of rain on the coast and "torrential downpours" in the Jalisco state capital of Guadalajara, government news agency Notimex said. They warned the hurricane could dump up to a foot of rain along parts of Mexico's southern coast, causing landslides or flooding. Dozens of communities were on alert, but no major problems had been reported.

Meanwhile, another weather system, Tropical Storm Kristy, formed in the Pacific far off the Mexican coast early Wednesday, but was forecast to move farther out to sea with no threat to land, the Hurricane Center said. Kristy had maximum sustained winds of 58 mph and was moving northwest at about 6 mph.